Asner, the seven-time Emmy Award-winner best known for his performances in “The Mary Tyler Moore Show,” “Lou Grant” and the animated film “Up,” will lead a discussion between presidential candidates Darrell Castle, of the Constitution Party; Gloria La Riva, of the Socialist Party, and Rocky De La Fuente, an independent candidate.

The debate is scheduled to begin at 7 p.m. Tuesday and will be held at Macky Auditorium on the Boulder campus. The United We Stand Festival, which is being held in conjunction with the debate, begins at 4 p.m. in Macky.

The event, which will be streamed online, is being organized by the Free and Equal Election Foundation, a nonprofit that seeks to broaden electoral choices.

The event is free and open to the public.

Kweku Mandela, grandson of the late Nelson Mandela, will deliver the keynote address at the debate.

Ramsey Clark, who served as U.S. attorney general under President Lyndon Johnson, is also expected to attend the festival, according to organizers.